The following patents are incorporated herein by reference: U.S. Pat. No. 6,760,038, issued Jul. 6, 2004, entitled “METHOD FOR RECOGNIZING BLENDS IN SOLID MODELS”; U.S. Pat. No. 7,042,451, issued May 9, 2006, entitled “METHODS USING SPECIFIC ATTRIBUTES AND GRAPH GRAMMARS IN GRAPH-BASED TECHNIQUES FOR FEATURE RECOGNITION”; and U.S. Pat. No. 6,597,355, issued Jul. 22, 2003, entitled “AUTOMATIC RECOGNITION AND SUPPRESSION OF COMPLEX INTERACTING HOLES.”
Traditionally, plastic part manufacturers receive Computer-Aided-Design (“CAD”) models or drawings from their clients and this is followed by a series of iterations during which the designs are modified taking into account ease of manufacturing and the tools available with the manufacturer. Many plastic part manufacturers have published guidelines related to designs when followed would lead to parts which are easy, cost effective and amenable to rapid manufacturing. Certain vendors also allow designs to be uploaded on their website for providing quotes.
A problem faced by organizations world-wide is how to reduce the time to market of a product. One of the areas of improvement is to reduce the back-and-forth design to manufacturing iterations. These iterations frequently occur due to various reasons—design has certain features which lead to increased cost or the design has features which may require usage of non-standard tools. For example, if a designer applies non-standard corner radii on a protrusion in a plastic model, the manufacturing department may have to procure an appropriate tool to machine the corresponding depression feature in the mold.
Many organizations have established guidelines and checklists and have put a manual design review process in place to reduce such problems. However, the lack of proper automation tools for evaluating the designs based on manufacturability parameters right in the designer's CAD environment poses difficulties in adoption and enforcement of the design review process.
Similarly, organizations all over the world experience a phase where the experienced workforce gradually retires as new engineers enter the design department. In such cases, the organization faces a significant loss of knowledge wherein best practices gained and lessons learnt over many years are lost. New design engineers lacking in experience on the manufacturing side, often tend to ignore manufacturing considerations in their design. This leads to increased number of design iterations which impacts cost and time to market. There is a need to capture the best practices prevalent in an organization as rules in software so that any design can be validated against them consistently.
Research has shown that most of the costs associated with the life cycle of a product are committed during the design phase. The costs involved are not only related to manufacturing but include everything right up to the disposal of the product. In today's environment, along with “design for manufacturing” (“DFM”), “design for assembly” (“DFA”), and “design for cost,” “design for maintainability” and “design for disposal” are equally important, the general term being Design for ‘X’, where X can be any of the above. Vendors have traditionally concentrated on addressing the “design for manufacturing” and/or “design for assembly” issues in software due to various reasons like demand and capability for automation. Even in the addressed domains, most approaches have been driven by the manufacturing process with no or partial automation.
In the mechanical CAD environment, most of the existing DFM/DFA solutions are based on calculating the costs associated with manufacturing and/or assembly of the product. These solutions are either based on activity roll up (activity based costing) or feature roll up (feature based costing). To arrive at a useful cost figure, these solutions require that the cost parameters like tool cost, labor rates and several others be customized according to local factors. These factors also vary based on manufacturing process. In parallel, small and large organizations world wide have been working with quick-win kind of DFM approaches which involve usage of global or organizational best practices or guidelines which are tried and tested and suited to the organizational methods of operation. It also involves design and manufacturing departments working together and, creating and following the best practices or guidelines.
Both approaches have their pros and cons. A cost based approach ensures a mathematical precision to decision making during design of parts. However, organizations share many costs across products; distributing these costs between the products may prove difficult in many cases. Not many of these solutions are integrated with CAD environments making these solutions difficult for a designer to practice and use on a continuous basis. Additionally, many design features may not affect cost directly but have an indirect impact in terms of quality of the product. This impact is not captured by many costing software.
A manual best-practice oriented DFM approach delivers knowledge and experience based wins but human errors during reviews present challenges. Another problem which manufacturers worldwide are trying to address is knowledge and best practice retention taking into account the ageing workforce and outsourcing of various parts of the manufacturing process.